Rotatable sample disk and method of loading a sample disk

ABSTRACT

A rotatable sample disk configured for samples of biological material. The sample disk may include a fill chamber for storing a first biological material, a plurality of first sample chambers positioned in the sample disk farther from the rotational axis of the sample disk than the fill chamber, a plurality of second sample chambers, and a plurality of circumferential fill channels. Each of the second sample chambers may be configured to permit fluid communication with a respective first sample chamber. The plurality of circumferential fill conduits may be configured to permit transfer of the first biological material from the fill chamber to the plurality of first sample chambers upon a first rotation of the sample disk about the rotational axis. Methods of loading a plurality of sample chambers in a sample disk are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/193,680 filed Jul. 12, 2002, which is incorporated herein in itsentirety by reference.

FIELD

The present teachings relate generally to a sample disk configured forsamples of biological material, and methods of loading a sample disk.The present teachings further relate, in various aspects, to a sampledisk that is rotatable about a rotational axis in order to centrifugallyload sample chambers of the sample disk with biological material.

BACKGROUND

Biological testing has become an important tool in detecting andmonitoring diseases. In the biological testing field, thermal cycling isused to amplify nucleic acids by, for example, performing polymerasechain reactions (PCR) and other reactions. PCR, for example, has becomea valuable research tool with applications such as cloning, analysis ofgenetic expression, DNA sequencing, and drug discovery. Methods such asPCR may be used to detect a reaction of a test sample to ananalyte-specific reagent. Typically, an analyte-specific reagent isplaced in each sample chamber in advance of performing the testing. Thetest sample is then later inserted into the sample chambers, and thesample well tray or microcard is then transported to a thermal cyclingdevice.

Recent developments in the field have led to an increased demand forbiological testing devices. Biological testing devices are now beingused in an increasing number of ways. It is desirable to provide a moreefficient and compact method and structure for filling and thermallycycling substrates such as sample trays and microcards.

In typical systems, the sample tray or microcard is loaded with reagent,then loaded with the test sample, and then transported and inserted intoa separate device for thermal cycling. It is desirable to reduce theamount of time and number of steps taken to fill and thermally cycle asample tray or microcard.

SUMMARY

Various aspects generally relate to, among other things, a rotatablesample disk configured for samples of biological material. According toone various aspects, the sample disk can include a fill chamber forstoring a first biological material, a plurality of first samplechambers positioned in the sample disk farther from a rotational axisthan the fill chamber, a plurality of second sample chambers, and aplurality of circumferential fill conduits positioned adjacent theplurality of first sample chambers. In various embodiments, the fillchamber is configured for rotation on the sample disk about a rotationalaxis. Each of the second sample chambers may be configured to permitfluid communication with a respective first sample chamber. The secondsample chambers may be positioned closer to the rotational axis than thefirst sample chambers. The plurality of circumferential fill channelsmay be configured to permit transfer of the first biological materialfrom the fill chamber to the plurality of first sample chambers upon afirst rotation of the sample disk about the rotational axis.

Various aspects comprise a method of loading a plurality of samplechambers on a sample disk. The method can include the step of providinga sample disk with a fill chamber, a plurality of first sample chambers,and a plurality of second sample chambers. The method may furthercomprise loading the plurality of first sample chambers with a firstbiological material by rotating the sample disk about a rotational axisso that a first biological material in the fill chamber travels througha plurality of circumferential fill conduits connecting the fill chamberwith the first sample chambers. The plurality of circumferential fillconduits may be positioned between adjacent first sample chambers. Themethod may further comprise providing a plurality of second samplechambers with a second biological material, and transporting the secondbiological material from the second sample chambers into the firstsample chambers by rotating the sample disk about the rotational axis sothat the second biological material passes from the second samplechambers through a plurality of radial fill conduits into the firstsample chambers.

Various aspects comprise an apparatus for centrifugally loading andthermally cycling a sample disk. The apparatus can comprise a sampledisk having a plurality of first sample chambers, a plurality of secondsample chambers, and a reservoir for storing a volume of liquid sample.The apparatus may further include means for centrifugally loading theplurality of first sample chambers with liquid sample upon rotation ofthe sample disk about a rotational axis of the sample disk. Theapparatus may further includes means for centrifugally loading theplurality of first sample chambers with a biological material from theplurality of second sample chamber. The apparatus may further include ameans for thermally cycling the plurality of first sample chambers ofthe sample disk.

Various other aspects comprise an apparatus configured for containingsamples of biological material during a thermal cycling operation. Theapparatus may include a microcard configured for rotation about arotational axis, a plurality of first sample chambers positioned on themicrocard around the rotational axis, and a plurality of second samplechambers positioned in the microcard around the rotational axis. Thesecond sample chambers may be positioned closer to the rotational axisthan the first sample chambers. The apparatus may further comprise aplurality of channels formed in the microcard. The plurality of channelsmay comprise a plurality of circumferential channels and a plurality ofradial channels. The circumferential channels may be positioned betweenadjacent first sample chambers to transport a first biological materialfrom a reservoir into the plurality of first sample chambers uponrotation of the microcard about the rotational axis. The plurality ofradial channels may be positioned between corresponding first and secondsample chambers to transport a second biological material from thesecond sample chambers to the first sample chambers upon a furtherrotation of the microcard about the rotational axis. The plurality offirst sample chambers may be configured to permit optical detection ofthe biological materials in the first sample chambers.

It is to be understood that both the foregoing general description andthe following description of various embodiments are exemplary andexplanatory only and are not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several exemplary embodiments. Inthe drawings,

FIG. 1A is a plan view of an exemplary embodiment of a sample diskaccording to the present teachings, prior to spinning the disk, with afirst biological material in a fill chamber;

FIG. 1B is a plan view of the sample disk of FIG. 1A after centrifugalloading of the first biological material into outer sample chambers ofthe disk;

FIG. 1C is a plan view of the sample disk of FIG. 1B, with a secondbiological material such as a test sample in inner sample chambers ofthe disk and with circumferential fill conduits being in a blockedstate;

FIG. 1D is a plan view of the sample disk of FIG. 1C after a secondcentrifugal loading operation, and with the circumferential fillconduits and radial fill conduits in a blocked state;

FIG. 2A is a cross-sectional view along line 2A-2A of FIG. 1A;

FIG. 2B is a cross-sectional view along line 2B-2B of FIG. 1B;

FIG. 2C is a cross-sectional view along line 2C-2C of FIG. 1C;

FIG. 2D is a cross-sectional view along line 2D-2D of FIG. 1D;

FIG. 3A is a plan view of a sample disk according to another embodimentof the present teachings, prior to filling a fill chamber with a testsample material;

FIG. 3B is a plan view of the sample disk of FIG. 3A after filling thefill chamber with a test sample material; and

FIG. 3C is a plan view of the sample disk of FIG. 3B, after centrifugalloading of the test sample material into the sample chambers, and radialfill conduits in a blocked state.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Reference will now be made to various exemplary embodiments, examples ofwhich are illustrated in the accompanying drawings. Wherever possible,the same reference numbers are used in the drawings and the descriptionto refer to the same or like parts.

In accordance with various embodiments, a rotatable sample diskconfigured for samples of biological material is provided. In oneaspect, the sample disk includes a fill chamber for storing a firstbiological material, a plurality of first sample chambers positioned inthe sample disk, a plurality of second sample disks, and a plurality ofconduits configured to permit transfer of the first biological materialfrom the fill chamber to the plurality of first sample chambers upon afirst rotation of the sample disk about a rotational axis of the sampledisk.

Although terms like “horizontal,” “vertical,” “upward,” “downward,”“radial,” and “axial” are used in describing various aspects of thepresent teachings, it should be understood that such terms are forpurposes of more easily describing the teachings, and do not limit thescope of the teachings.

In various embodiments, such as illustrated in FIGS. 1-2, a sample disk10 is provided. The sample disk 10 may be configured for thermallycycling samples of biological material in a thermal cycling device. Thethermal cycling device may be configured to perform nucleic acidamplification on samples of biological material. One common method ofperforming nucleic acid amplification of biological samples ispolymerase chain reaction (PCR). Various PCR methods are known in theart, as described in, for example, U.S. Pat. Nos. 5,928,907 and6,015,674 to Woudenberg et al., the complete disclosures of which arehereby incorporated by reference for any purpose. Other methods ofnucleic acid amplification include, for example, ligase chain reaction,oligonucleotide ligations assay, and hybridization assay. These andother methods are described in greater detail in U.S. Pat. Nos.5,928,907 and 6,015,674.

In various embodiments, the sample disk may be used in a thermal cyclingdevice that performs real-time detection of the nucleic acidamplification of the samples in the sample disk during thermal cycling.Real-time detection systems are known in the art, as also described ingreater detail in, for example, U.S. Pat. Nos. 5,928,907 and 6,015,674to Woudenberg et al., incorporated herein above. During real-timedetection, various characteristics of the samples are detected duringthe thermal cycling in a manner known in the art. Real-time detectionpermits more accurate and efficient detection and monitoring of thesamples during the nucleic acid amplification process. Alternatively,the sample disk may be used in a thermal cycling device that performsendpoint detection of the nucleic acid amplification of the samples. Onetype of detection apparatus that may be used with the present teachingsfor either real-time or endpoint detection is the LightCycler.™.Instrument manufactured by Roche Molecular Biochemicals. Another type ofdetection apparatus includes a single LED sensor for detecting thecharacteristics of the samples as the sample disk rotates about arotational axis. Several other types of detection apparatus are shown inWO 02/00347A2 to Bedingham et al., the complete disclosure of which ishereby incorporated by reference for any purpose.

As shown in FIG. 2D, a sample disk 10 may be configured to contact asample block 300 for thermally cycling the biological materials in thesample chambers of the sample disk. The sample block may be operativelyconnected to a temperature control unit 302 programmed to raise andlower the temperature of the sample block according to a user-definedprofile. For example, in various embodiments, a user may supply datadefining time and temperature parameters of the desired PCR protocol toa control computer that causes a central processing unit (CPU) of thetemperature control unit to control thermal cycling of the sample block.Several non-limiting examples of suitable temperature control units forraising and lowering the temperature of a sample block for a microcardor other sample-holding member are described in U.S. Pat. No. 5,656,493to Mullis et al. and U.S. Pat. No. 5,475,610 to Atwood et al., thedisclosures of which are both hereby incorporated by reference for anypurpose.

In one embodiment, the rotatable sample disk comprises at least one fillchamber on the rotatable sample disk, a plurality of first samplechambers, a plurality of second sample chambers, and a plurality of fillconduits. One embodiment of a sample disk of the present teachings isshown in FIGS. 1-2. As embodied herein and shown in FIGS. 1-2, therotatable sample disk is a microcard or sample tray generally designatedby reference number 10. The sample disk is generally rotatable about arotational axis 12. The rotatable sample disk 10 is shown as being acircular plate, however, it is understood that the sample disk may beany other suitable shape such as rectangular or square. A circular shapeis shown merely because a circular shape will typically minimize theamount of space taken up by the sample disk as it rotates aboutrotational axis 12.

As shown in FIGS. 1-2, particularly FIG. 2A, the rotatable sample diskmay include a first layer 14 and second layer 16. For purposes ofconvenience, the first layer may be referred to as the “top layer” andthe second layer may be referred to as the “bottom layer.” As shown forexample in FIG. 2A, the first layer 14 includes a top surface 18 andbottom surface 20. The second layer 16 generally includes a top surface22 and a bottom surface 24. The first and second layers may be made outof any suitable material or materials. In a typical embodiment, thefirst layer 14 is made of a polymeric material such as polypropylene andthe second layer 16 is made out of a metal such as metal foil.Alternatively, both the first layer 14 and the second layer 16 may bemade out of a polymeric material. In another embodiment, the first layeris made out of polypropylene and the second layer is made out of lexan.Other suitable polymers include polyester, polycarbonate, andpolyethylene.

In the embodiment shown, the first layer 14 includes all of the featuresof the sample chambers, fill conduits, and fill chambers in a polymericsheet that has been molded, vacuum formed, pressure formed, compressionmolded, or otherwise processed. The second layer 16 is provided as asubstantially flat plate that is attached to the first layer 14 tocomplete formation of the features of the sample chambers, fillconduits, and fill conduits. It should be understood that the featuresmay be provided in both layers of the sample disk. It may be desiredthat the first and second layer are made out of PCR-compatiblematerials. It may also be desirable that the materials selected for thefirst and second layer exhibit good water barrier properties.

A variety of methods of forming the layers and methods of adhering thetwo layers together are described in, for example, WO 02/01180A2 toBedingham et al., the complete disclosure of which is herebyincorporated by reference for any purpose, and WO 02/00347A2 toBedingham et al., incorporated herein above. The structure of the firstand second layers will be described in greater detail below, as thestructure of the first and second layers define the sample chambers,fill chambers, and fill conduits that comprise sample disk 10.

In various embodiments, the sample disk includes at least one fillchamber for storing a first biological material, and a plurality offirst sample chambers. As embodied herein and shown in FIGS. 1A-1D, thesample disk includes a fill chamber 28 positioned on the upper layer 14of the sample disk, and a plurality of first sample chambers 40 (alsoreferred to as “outer sample chambers”). The fill chamber of oneembodiment of the present teachings serves as a reservoir for storingthe first biological material prior to the sample disk being rotated tocentrifugally load the first biological material into the outer samplechambers.

In the embodiment shown in FIGS. 1-2, the first biological materialwould typically be a reagent, particularly an analyte-specific reagent.Analyte-specific reagents are well-known in the art. It should beunderstood that the first biological material may be any other type ofsuitable biological material, such as a test sample material, instead ofa reagent. For purposes of conveniently describing the embodiment ofFIGS. 1-2, the first biological material will be described as a reagent.In the embodiment shown in FIGS. 1-2, the user can select an appropriatereagent or other biological material, thereby providing more flexibilitycompared to testing devices in which the reagents are pre-programmedinto the testing device. If the sample disk provides for a single“primary” fill chamber 28, one reagent may be used in a single sampledisk.

The fill chamber may have any type of shape suitable for storing aliquid. In the example shown in FIGS. 1A-1D, the fill chamber 28 isshown as being generally oval, however any other suitable shape isacceptable. The volume of the fill chamber can range from quite large tovery small, depending on the desired amount of reagent (or other firstbiological material) for each of the outer sample chambers 40 into whichit will be centrifugally loaded in a manner described below. Typically,the total amount of reagent placed in the fill chamber will bepredetermined prior to entry of the reagent into the fill chamber 28.The amount of volume may be calculated based on the amount of reagentdesired in each sample chamber, multiplied by the total number of samplechambers on the sample disk. By way of example only, in an embodiment inwhich there are seventy-two sample chambers 28, the predetermined amountof reagent to be inserted into the fill chamber 28 may be seventy-twotimes the amount of reagent desired in each outer sample chamber. Forexample, in a scenario in which it is desired that each of theseventy-two outer sample chambers eventually contain approximately 5 μlof reagent, then the approximate total volume of the fill chamber wouldbe approximately 360 μl. The desired amount of reagent can greatly varyhowever, depending on a large number of factors.

In various embodiments, the fill chamber may include an orifice forpermitting loading of the first biological material into the fillchamber. As shown in FIGS. 1A-1D, orifice 30 may be provided on theoutside of the fill chamber 28. The orifice 30 is typically sized inorder to permit pipetting of the first biological material, such as areagent, into the fill chamber. Alternatively, the fill chamber may befilled by any other acceptable method for inserting a first biologicalmaterial such as a reagent into a reservoir. It should be understoodthat although the drawings only illustrate a single fill chamber 28, itis easily understood that the sample disk could have any number of“primary” fill chambers. The fill chambers could be positioned aroundthe rotational axis, typically in a concentric and evenly spaced mannerin order to promote a uniform distribution of the first biologicalmaterial into the sample chambers.

In various embodiments, the sample disk includes a plurality of firstsample chambers, a plurality of second sample chambers, and a pluralityof fill conduits. In the embodiment shown in FIGS. 1-2, the sample diskincludes a plurality of first sample chambers (or “outer samplechambers”) 40 and a plurality of second sample chambers (or “innersample chambers”) 48. As shown for example in FIG. 1A, the plurality ofouter sample chambers 40 are positioned concentrically about therotational axis of the 12. It is also contemplated that the outer samplechambers may be positioned non-concentrically, however it is typicallydesired to have the outer sample chambers positioned concentrically toenhance uniform volumes of biological material in each of the outersample chambers. The outer sample chambers 40 may be equally spaced fromone another as shown in FIGS. 1A and 1B, or the spacing may be varied.

The sample chambers may have any shape suitable for thermal cycling. Inthe embodiment shown in FIGS. 1-2, the outer sample chambers 40 arecylindrical with flat top surface 44, however, any other known shape isalso suitable. In a typical system, light may be transmitted through thetop surface of the outer sample chambers during detection of thecharacteristics of the biological material in the sample chamber. Asbest seen in FIG. 2A, outer sample chamber 40 is formed by a raised flattop surface 44 of first layer 14 that creates a space between the firstlayer and the top surface 22 of second layer 16. The raised flat topsurface 44 may be formed by any known method. The outer sample chamber40 defines a volume for storing biological materials.

In the embodiment shown in FIG. 1A, a total of seventy-two (72) outersample chambers are included on the sample disk, however it is possibleto use anywhere from one to at least several thousand outer samplechambers. The outer sample chambers are preferably configured to bePCR-compatible, and typically have a surface such as top surface 44through which an optical detection system (not shown) can detect thecharacteristics of sample materials stored in the sample chambers. Theconcept of sample chambers is known in the art. In a more typicalembodiment, the size of the sample chambers may vary from 0.1 μl toseveral thousand μl. In a more typical embodiment such as shown in FIG.1, the outer sample chambers 40 are configured to have a volume ofapproximately 10 μl. It should be understood that this volume is forpurposes of example only. In some instances, it may be desirable to havesmaller volumes in order to reduce the amount of reagent and samplematerial required to load the sample disk. In other instances, it may bedesirable to have a greater volume. In various embodiments, the chambersare configured to hold no greater than 1,000 μl. In other embodiments,the chambers are configured to hold no more than 200 μl, no more than100 μl, no more than 50 μl, or no more than 0.5 μl.

In accordance with various embodiments, the sample disk includes aplurality of fill conduits configured to permit transfer of a firstbiological material from the fill chamber to the plurality of firstsample chambers upon rotation of the sample disk about the rotationalaxis. As embodied herein and shown in FIGS. 1A and 1B, the plurality offill conduits includes a plurality of circumferential fill conduits 42positioned between adjacent outer sample chambers 40. In the embodimentshown in FIG. 1A, the circumferential fill conduits 42 are positionedconcentrically about the rotational axis 12 at a fixed diameter. Itshould be understood that the circumferential fill conduits do notnecessarily need to be concentrically spaced from the rotational axis12. In FIGS. 1A and 1B, the circumferential fill conduits 42 are shownbisecting the center of the sides of each of the outer sample chambers40. The circumferential fill conduits are designed to permit fluidcommunication between adjacent outer sample chambers. In the embodimentshown, the circumferential fill conduits 42 are defined by featuresformed in the first layer 14 that create a space with the top surface 22of the second layer 16. The features in the first layer may be formed byany known processing method such as, but not limited to, molding, vacuumforming, pressure forming, and compression molding. In variousembodiments, the fill conduits (or channels) described herein may have arange of sizes. In various embodiments, such conduits have at least onecross-sectional dimension, e.g., width, depth, or diameter, of between 1to 750 micrometers. In various other embodiments, such conduits have atleast one cross-sectional dimension of from between 10 to 500micrometers, or from between 50 to 250 micrometers.

In various embodiments, the sample disk comprises a primary fill conduitextending from the fill chamber to the circumferential fill conduitsand/or outer sample chambers. As shown in FIGS. 1A-1D, a primary fillconduit 46 may extend between the fill chamber 28 to one of thecircumferential fill conduits 42. In one embodiment, the primary fillconduit 46 extends radially in order to transport the reagent in thefill chamber to the circumferential fill conduit 42 upon rotation of thesample disk about rotational axis 12. The primary fill conduit may besized to prevent the first biological material, typically reagent R,from passing through it while the sample disk is stationary. If theprimary fill conduits are an appropriate size and shape, the surfacetension of the interior surface of the conduit will prevent the flow ofthe reagent through the primary fill conduit when the sample disk is ata resting position (or rotating at a speed below a predetermined speedat which the reagent will begin to flow due to centrifugal force).

It should be understood that the primary fill conduit need not becompletely radial in order to transport the reagent. Likewise, it shouldalso be understood that, in some embodiments, the primary fill conduitcould be eliminated by moving the fill chamber closer to or adjacent thecircumferential fill conduit. Although only one primary fill conduit 46is shown in FIGS. 1A-1D, it is contemplated that several fill conduitscould be used, particularly in embodiments having a plurality of fillchambers. For example, it is conceivable to have the same number of fillchambers as outer sample chambers. In such an embodiment, each fillchamber may have an individual primary fill conduit. With an embodimenthaving seventy-two outer sample chambers, a total of seventy-two fillchambers and seventy-two primary fill conduits might be provided. It isof course contemplated that a smaller number of fill chambers andprimary fill conduits could also be used.

It should also be understood that several sets of fill chambers andouter sample chambers may be provided. In one embodiment, each set offill chambers and one or more sample chambers could use separate samplesto be tested. This would allow for a large amount of samples to betested on a single sample disk. In another embodiment, each fill chambercould be ganged with one or more outer sample chambers. It should alsobe understood that a plurality of disks could be stacked together.

The sample disk may further include a plurality of inner sample chamberspositioned radially inside of the outer sample chambers. In theembodiment shown for example in FIGS. 1A and 2A, the inner samplechambers 48 are similar in shape to the outer sample chambers 40. Theinner sample chambers 48 however may have any shape suitable for storinga second biological material. Inner sample chambers 48 may be positionedcloser to the rotational axis 12 than the outer sample chambers 40,i.e., radially inside of the outer sample chambers. In the embodimentshown in FIGS. 1-2, the inner sample chambers 48 may be used to store asecond biological material, typically the sample material to be tested,after a first biological material such as a reagent has beencentrifugally loaded from the fill chamber to the outer sample chambers40. After the reagent has been centrifugally loaded into the outersample chambers as shown in FIGS. 1B and 2B, the inner sample chambers48 may be filled with a sample to be tested.

As shown in FIG. 1A, in a typical arrangement, an equal number of innersample chambers and outer sample chambers are provided. In the exampleshown in FIG. 1A, the sample disk includes seventy-two inner samplechambers 48 and seventy-two outer sample chambers 40. It is understoodthat any other number of inner sample chambers may be provided. In theembodiment shown, the inner sample chambers 48 are approximately thesame size as the outer sample chambers 40, however this can be varieddepending on the specific application. For example, in a sample diskconfiguration in which it is desired to use a large amounts of reagentand a small amount of test sample material, it may be desired to haveinner sample chambers that are smaller than the outer sample chambers.Likewise, in the situation where it is not desired to completely fillthe outer sample chambers, it may also be desired to have inner samplechambers that are smaller than the outer sample chambers.

In accordance with various embodiments, radial fill conduits may beprovided between the second sample chambers and the first samplechambers. In the embodiment shown in FIG. 1, the second or inner samplechambers 48 and first or outer sample chambers 40 are connected byradial fill conduits 50. As shown in FIG. 1A, radial fill conduit 50extends in a radial direction with respect to rotational axis 12. FIG.2A illustrates a cross-section along line 2A-2A of FIG. 1A which passesthrough radial fill conduit 50. As can be seen in FIG. 2A, radial fillconduit is configured to permit fluid communication between the innersample chamber 48 and outer sample chamber 40. The radial fill conduitis defined by a raised portion 52 in the first layer 14 of the sampledisk, and a top surface 22 of the second layer 16 of the sample disk.The raised portion is formed in the first layer 14 by any known method.The radial fill conduits are typically sized in depth so that fluid onlypasses through the conduit upon a centrifugual force being imparted onthe sample disk.

The radial fill conduits 50 are shown having approximately the same sizeas the circumferential fill conduits 42, however the size and shape ofthe radial fill conduits may be varied. As will be described later, theradial fill conduits permit transfer of a second biological materialfrom the inner sample chambers 48 to the outer sample chambers 40 uponrotation of the sample disk. In the embodiment described herein, theloading of the second biological material, e.g., sample to be tested,into the outer sample chambers typically occurs after the firstbiological material, e.g., reagent, has already been pre-loaded into theouter sample chambers. This will be discussed in greater detail in thedescription of the operation of the sample disk.

In various embodiments, the inner sample chambers 48 may include anorifice for permitting loading of the second biological material intothe inner sample chamber. As shown in FIGS. 1A and 2A, for example, anorifice 54 may be formed in the top surface 56 of inner sample chamber48. The orifice allows for manual or automatic loading of the secondbiological material, typically the sample test material, into the innersample chamber 48. A typical method of loading the sample test materialis pipetting. Other methods may also be utilized however. Instead of anorifice, any other known type of structure for permitting entry of aliquid into a reservoir may also be used.

In various embodiments, a means for selectively blocking the passage ofthe first biological material through the circumferential fill conduitsis provided. The blocking of the passage of the first biologicalmaterial, typically a reagent, through the circumferential fill conduitsis particularly useful after the reagent has already been centrifugallyloaded from the primary fill conduit into the outer sample chambers. Theblocking assists in preventing cross-contamination between adjacentouter sample chambers. In the embodiment shown in FIG. 1C, the firstlayer 14 of the sample disk may be physically deformed at position 60 bya staking device in order to block or occlude the circumferential fillconduits 42. The staking device may be any device that is configured forphysically deforming the circumferential fill conduit, such as a knifeedge. Alternatively, the second layer 16 may be physically deformed inorder to block or occlude the circumferential fill conduits. Thematerials of the sample disk are typically selected so that staking mayeffectively occur.

It should be understood, however, that the complete sealing or occludingof the circumferential fill conduits may not be required. For example,it may only be required that the deformation restrict flow, migration ordiffusion through a conduit or fluid passageway sufficient to providethe desired isolation of adjacent outer sample chambers. As used inconnection with the present teachings, “blocking” or “occlusion” or“closing” will include both partial blocking and complete blocking.

In order to promote more effective blocking, it may be desired to useany other known means for blocking a conduit. For example, it may beuseful to use adhesives on either or both of the first and second layerin order to promote sealing of the conduit after the layers aredeformed. Instead of physical deformation, the means for blocking mayalso comprise any other type of melting, bonding, and welding in orderto block off the circumferential fill conduit. A number of suitablemethods of blocking or occluding a conduit of a microcard are describedin WO 02/01180A2 to Bedingham et al., incorporated by reference above.

In various embodiments, a means for selectively blocking the passage ofthe first and second biological material from the outer sample chambersto the inner sample chambers is provided. The means for blocking isutilized after the biological sample material to be tested, shown as Sin FIG. 1C, has been centrifugally loaded from the inner sample chambers48 into the outer sample chambers 40. When the sample to be tested iscentrifugally loaded into the outer sample chamber 40 it mixes with thereagent, shown as R, which was previously loaded into the outer samplechambers 40 as shown in FIGS. 1B and 2B. After the sample to be testedis loaded into the outer sample chambers, it is desired maintain thesample and reagent in the outer sample chambers. A number of differentmethods and structures may be used to block the radial fill conduits inorder to maintain the sample and reagent in the outer sample chambers.

For example, FIGS. 1D and 2D show an embodiment in which the first layer14 of the sample disk is physically deformed at position 70 by a stakingdevice, such as a knife edge, in order to block passage of the liquidsout of the outer sample chambers. FIG. 2D shows the physically deformedportion 70 of the first layer 14 that has been pressed downward by astaking apparatus in order to block or occlude the passage of liquidthrough radial fill conduit 50. This blocking is useful so that aconstant volume of material is maintained in each of the outer samplechambers 40 during thermal cycling and detection of the sample chambers.This will be discussed in greater detail in the description of theoperation of the sample disk.

An example of the operation of the sample disk for the embodiment ofFIGS. 1-2 is described below. In the first step of the operation, asample disk is provided. As shown in FIG. 1A, the sample disk 10 of oneembodiment includes, among other things, a fill chamber 28, a primaryfill conduit 46, a plurality of outer sample chambers 40, a plurality ofinner sample chambers 48, a plurality of circumferential fill conduits42, and a plurality of radial fill conduits 50. The sample disk 10 istypically placed on the drive shaft of a centrifuge in a thermal cyclingdevice (not shown) so that the sample disk may rotate about rotationalaxis 12.

Next, a first biological material may be loaded into the fill chamber 28positioned on the sample disk. As previously discussed, the firstbiological material in the embodiment of FIGS. 1-2 is typically areagent. For the sake of ease of discussion, the first biologicalmaterial will be referred to as a reagent. It should be understoodhowever, that the first biological material may instead be the sample tobe tested. The reagent is labeled R in FIG. 1A. The reagent may beloaded into the fill chamber 30 by any suitable method. One method is topipette the reagent through orifice 30 positioned on top of the fillchamber 28. In the position shown in FIG. 1A, the reagent fills the fillchamber 28 but does not pass along the primary fill conduit 46 due tothe surface tension of the reagent on the primary fill conduit. As shownin FIG. 2A, the outside sample chamber 40 and inner sample chamber 48are initially empty.

After a predetermined amount of reagent has been loaded into the fillchamber 28, the sample disk 10 is rotated about the rotational axis bythe centrifuge (not shown). Upon reaching a certain rotational speed,the centrifugal force will cause the reagent R to flow through theprimary fill conduit 46 and through the circumferential fill conduits 42into the outer sample chambers 40 until the reagent is evenlydistributed throughout the outer sample chambers as shown in FIGS. 1Band 2B. In one exemplary embodiment, the reagent fills approximatelyhalf of each outer sample chamber, as shown in FIGS. 1B and 2B. Becauseof the centrifugal force, the reagent will fill the half of the outersample chamber farthest from rotational axis 12. It should be understoodthat a greater amount of reagent may be used. A smaller amount ofreagent may also be used. If a smaller amount of reagent is used, thesample disk may be modified so that the circumferential fill conduits 42are positioned farther from the rotational axis 12 than shown in FIGS.1-2. The circumferential fill channels would be moved closer to theouter edge of the outer sample chambers 40.

It should of course be understood that the centrifugal force to causeloading of the outer sample chambers may be created by any number ofrotations, including less than a full rotation.

The circumferential fill conduits 42 shown in FIGS. 1-2 may now bestaked by any known method such as physical deformation of the firstlayer 14 of the sample block to occlude the passage of fluid through thecircumferential fill conduits 42. FIGS. 1C and 2C show thecircumferential fill conduits 42 being staked at position 60 to preventfluid communication between adjacent outer sample chambers 40.

After the circumferential fill conduits 42 have been staked, a secondbiological material, typically a sample S to be tested, may be loadedinto the inner sample chambers 48. It should be understood that thesecond biological material may instead be a reagent or other type ofbiological material. In one embodiment, the test sample S is insertedinto some, if not all, of inner sample chambers 48 shown in FIGS. 1C and2C through orifice 54 on the top surface 56 of the inner sample chamber48. The surface tension of the sample prevents the sample from initiallyflowing through the radial fill conduit 50 into the outer sample chamber40.

After the sample S has been loaded into the inner sample chambers 48,and the circumferential fill conduits 42 have been staked, both as shownin FIGS. 1C and 2C, the sample disk is rotated again about therotational axis 12. Upon rotation of the sample disk at a certain speed,the sample S to be tested will be urged by centrifugal force to flowfrom the inner sample chambers 48 through the radial fill conduits 50into the outer sample chambers 40. The sample to be tested flows intothe outer sample chambers 40 and mixes with the reagent R to form afinal test material labeled F in FIGS. 1D and 2D. After the sample to betested has been loaded into the outer sample chambers, the radial fillconduits 50 are staked to maintain the final test material F (comprisingthe reagent and the sample to be tested) in the outer sample chambers40. As shown in FIG. 2D, the radial fill conduit may be staked, in oneembodiment, by physically deforming a portion of the top surface of thefirst layer 14 in a region intersecting the radial fill conduit. Theportion of the top surface that is deformed is labeled as referencenumber 70 in FIG. 2D. After the radial fill conduit is sufficientlyblocked, the sample disk may be further rotated and thermally cycled.

During rotation and thermal cycling of the sample block, in oneembodiment, the optical characteristics of the final sample F can bedetected by an optical detection system. In one embodiment, the opticaldetection system is similar to the LightCycler™ system of Roche.

In this embodiment, the sample disk may be maintained about a singlerotational axis for the processes of filling the sample chambers,thermally cycling the samples, and optically detecting the samples. Bysuch an operation, the cost and time spent loading the sample chambersand thermally cycling the sample chambers may be minimized. Moreover, byproviding a sample disk that can be loaded by rotating about a singlerotational axis, it is possible to provide an integrated centrifuge andthermal cycling device. Such an integrated centrifuge and thermalcycling device could conceivably be a portable apparatus that can beuseful for point of service analysis.

As is clear from the above description, the present teachings includemethods of centrifugally loading a plurality of sample chambers in asample disk. The method may comprise providing a sample. An apparatusfor centrifugally loading and thermally cycling a sample disk,comprising: a sample disk having a plurality of first sample chambers, aplurality of second sample chambers, and a reservoir for storing avolume of liquid sample; means for centrifugally loading the pluralityof first sample chamber with liquid sample upon rotation of the sampledisk about a rotational axis of the sample disk; and means forcentrifugally loading the plurality of first sample chambers with abiological material from the plurality of second sample chambers; andmeans for thermally cycling the plurality of first sample chambers ofthe sample disk.

After the sample S to be tested has been loaded into the sample chambersto join the already inserted reagents R to form final test material F,the sample disk may be staked. As shown in FIG. 3C, the radial fillconduits 126 may be staked, in one embodiment, by physically deformingportion 130 of the top layer of the sample disk in a manner similar tothat performed on radial fill conduits 50 in the FIG. 1-2 embodiments.After the radial fill conduit is sufficiently blocked, the sample diskmay be further rotated and thermally cycled. During or after thermalcycling, the optical characteristics of the final sample F may bedetected by an optical detections system. In one embodiment, the opticaldetections system is similar to the LightCycler™ system of RocheMolecular Biochemicals.

As is clear from the above description, the present teachings may alsoinclude a method of centrifugally loading and thermally cycling aplurality of sample chambers on a sample disk.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure and methodsdescribed above. Thus, it should be understood that the presentteachings are not limited to the examples discussed in thespecification. Rather, the present teachings are intended to covermodifications and variations.

1. An apparatus for centrifugally loading and thermally cycling a sampledisk, comprising: a sample disk having a plurality of first samplechambers, a plurality of second sample chambers, and a reservoir forstoring a volume of liquid sample, each second sample chamber in fluidcommunication with a respective first sample chamber, means forcentrifugally loading the plurality of first sample chambers with liquidsample upon rotation of the sample disk about a rotational axis of thesample disk, and comprising a plurality of circumferential fill conduitspositioned circumferentially around the sample disk, eachcircumferential fill conduit being positioned between a respective pairof adjacent first sample chambers of the plurality of first samplechambers, the circumferential fill conduits in fluid communication withthe reservoir to permit transfer of the liquid sample from the reservoirto the plurality of first sample chambers, means for centrifugallyloading the plurality of first sample chambers with a biologicalmaterial from the plurality of second sample chambers; and means forthermally cycling the plurality of first sample chambers of the sampledisk.
 2. The apparatus of claim 1, wherein the means for thermallycycling comprises a sample block thermally connected to the sample disk.3. The apparatus of claim 2, wherein the means for thermally cyclingfurther comprises a temperature control unit operatively connected tothe sample block for raising and lowering the temperature of the sampleblock according to a user-defined profile.
 4. An apparatus forcentrifugally loading and thermally cycling a sample disk, comprising: asample disk having a plurality of first sample chambers, a plurality ofsecond sample chambers, and a reservoir for storing a volume of liquidsamples; a plurality of circumferential fill conduits each positionedbetween a respective pair of adjacent first sample chambers of theplurality of first sample chambers, the plurality of circumferentialfill conduits arranged circumferentially around the sample disk andconfigured to permit transfer of the material from the reservoir to theplurality of first sample chambers upon a first rotation of the sampledisk about a rotational axis; and a thermal cycler for thermally cyclingthe plurality of first sample chambers, wherein each second samplechamber is configured to permit communication with a respective firstsample chamber, and the second sample chambers are positioned closer tothe rotational axis than the first sample chambers.
 5. The apparatus ofclaim 4, wherein the thermal cycler comprises a sample block thermallyconnected to the sample disk.
 6. The apparatus of claim 5, wherein thethermal cycler comprises a temperature control unit operativelyconnected to the sample block for raising and lowering the temperatureof the sample block according to a user-defined profile.
 7. Theapparatus of claim 4, wherein the sample disk comprises a top layer anda bottom layer, wherein the bottom layer comprises a metal.
 8. Theapparatus of claim 7, wherein the lop layer comprises polypropylene. 9.The apparatus of claim 4, wherein each of the plurality of first samplechambers has a volume of no more than 100 microliters.
 10. The apparatusof claim 4, wherein each circumferential fill conduit is positionedconcentrically about the rotational axis of the sample disk at a fixeddiameter.
 11. The apparatus of claim 4, wherein the plurality ofcircumferential fluid conduits is positioned to permit fluidcommunication between the plurality of first sample chambers.
 12. Theapparatus of claim 4, wherein the first sample chambers are positionedin the sample disk farther from the rotational axis of the sample diskthan the reservoir, and the second sample chambers are positioned in thesample disk closer to the rotational axis of the sample disk than arethe first sample chambers.